Article storage facilities such as one described above have a purging function whereby inactive gas is supplied to transporting containers stored in storage sections to prevent degradation of substrates in the transporting containers. As a specific example, a storage shelf, including a plurality of storage sections for storing transporting containers such as FOUPs for housing semiconductor wafers, is configured as an article storage shelf with a purge function. This article storage shelf includes, for each of the storage sections, a supply nozzle as an inactive gas feed section which supplies inactive gas, such as nitrogen gas and gaseous argon, to the interior of respective transporting container.
An example of such an article storage facility is disclosed in JP Publication Of Application No. 2010-16199 (Patent Document 1), which describes the following technology for reducing the amount of inactive gas consumption as much as possible to reduce the running cost of the facility. The technology involves a capability to change the flow rate of the inactive gas injected from the supply nozzle depending on whether the transporting container is stored in the storage section, such that the flow rate of inactive gas for when the transporting container is not stored in the storage section is less than the flow rate for when the transporting container is stored in the storage section.
More specifically, in the facility of Patent Document 1, the flow rate of inactive gas for when the transporting container is stored in the storage section is set to be a flow rate necessary to supply sufficient amount of inactive gas to the transporting container (referred to as the “first flow rate”). On the other hand, the discharge flow rate for when the transporting container is not stored in the storage section is designed to prevent impurities (i.e. contaminants), such as particles and vapor, from accumulating in the inactive gas feed section and is set to a flow rate (referred to as the “second flow rate”) which is less than the first flow rate. This helps prevent the impurities that causes degradation of the substrates from accumulating in the inactive gas feed section while the transporting container is not stored in the storage section. Thus, efforts are made to reduce running cost of the facility while retaining the facility's ability to supply inactive gas that is as pure as possible, to the transporting container after the transporting container is stored in the storage section.
However, in the facility of Patent Document 1, the inactive gas is normally emitted to the open space from the supply nozzle at the second flow rate when the transporting container is not stored in the storage section. Thus, there is a problem that a large amount of inactive gas is wasted since the inactive gas which should have been supplied to a transporting container is released to open space without being supplied to the transporting container.